Clamping device



May 6, 1930.

H. L. MYERS CLAMPING DEVICE Filed Jan. 26, 1928 Inventor -Harr y L Myers Patented May 6, 1930 UNITED. STATES' PATENT optics HARRY L. MYERS, or TOLEDO, OHIO, Assrenoa r Til-i1}? AMERICAN rtoon 'snnmcms MACHINE COMPANY, or Tonnno, onto cLAMrINe Device;

Application filed January '26, 1928. Serial Nq;'249,649.

This invention relates to an improved sanding drum of the type employed upon a rotary abrading or sending machine More precisely, the invention comprehends an improved drum and paper retainer which is expressly intended for use upon the ma chine shown and described in a' (so-pending application for patent,.filed under date of' January 12, 1928, and designated by Sepia] No. 246,198. I y

I am aware that it is now customary in.

structures of this class to have a cylindrical drum around which the abrading paper is wrapped. and to provide the drum with ya longitudinal slot, through which the ends 'of the paper are turned in. Usuallvthe inturned ends are bound" or clamped in "place by the drawing action of; a pair OLE-rotary clamping rods mounted uponthedrum in close proximity to theslots.

Then too, it is customaryto have the opposed surfaces of the rods flat, to enhance the clamping'action.

The utilization of knurled bars with flat clamping faces, has been used for some time as sand paper clamping means in machines of this class. from the use mounted clamping rods. where the bars are removable or replaceable or originally assembling them into place.

caring in mind, the manufacturing dis advantages accruing from the present conditions, and having in mind, the expense imposed upon the user necessary, I have evolved and produced a structural arrangement wherein the clamping bars are removably mounted in the heads i I at the ends of the drum in a manner to fa-' cilitate assembly, removal and replacement,

showing the improved drum and the means so for mounting one of the clamping bars. I

An objection arises however, of rigidly or permanently In rare IDStaIICGS difliculty is experienced in changing the bars in the event repair is Fig. 2 is an end view, showing the relative positions offthe bars with respect to the end heads and slots. 7

Referring now to the drawings "by numerals, it will be. seen that the numeral- 3 designates generally theimproved drum the shell of which iscylindrical in cross section and providedon-one side with a longitudinal slot 4 extending through the opposite ends of'the shellg It is understood that the sand paper orcljoth backed abrasive is wrapped around the shell of the drum .in'the usual way and-'the'ends tucked into the slot where they r are engaged with the held in place.

p In the present instance, the drum is provided withend heads includingweb' portions clamping; means and 5 disposed in inwardly spaced relation from the ends of the shell. formed with radial slots 6 in communication with the. aforesaid slot at. With'this'1arrangemerit, the extremities .of portions-ofthe abrasive :paper canfbe accommodated throughout theirlengthpn I In other words, the-slot whichaccommodates the inturned' edgesof the. paper is commensurate 'withsthe width of thepaper used. Formed in each web sides o'f-the slot 6, we, find a pair of bearing balsam-openings, whichinthe present instance,receiveremovablebushings-7 as shown in- Fig. l.- The bushingsare driven'into place andxheld firmly by-friction. t

Cooperating with each pair ofcompanion bushings is; a clampingsrod 8, ha-ving'a central knurled surface 9 andhere formed with afiat clampingface. The end portions of. the rod are reduced and made into smooth surfacedjournals, and extended through and beyond thebushings7. The reduction in diametersimultaneously provides shoulders whichabut theainner ends of the comple- The portions=5 are:

the inturned edge portion 5 on oppos1temental bushings as shownin Fig. 1. The left 1 hand end of the rod is flush with the corresponding-end-of the drum while the right handendincludes an extension 11 which is r made polygonal and provides a wrench grip. Figure 1 is a vlew in longitudinal section Fitted on the protruding end portions of I each rod are externally knurled clamping tened in place. These sleeves bear at their inner ends against the outer ends of the bushings. c

The construction herein illustrated and specifically described possesses several prominent advantages. First, it makes it possible to use an abrasive with a paper back, instead of a cloth back in a small cylinder type machine. Obviously, this is of great economic value,-thediflerence in cost'being aboutonethird of the total cost of the abrasive."

It will be noted that the arrangement prO-. vides for the bushings to be placed inwardly. from the end flanges of the drum, and that the knurled sleeves fitted onto the protruding portions, operate in such a manner as to clamp the outside edges of the paper as itis fed through thelongitudinal and radial slots provided for'thesame. This thereby makes it possibleto clamp the paper onthe outside edges, as well as at the center, a very practical feature in an invention ofthis class.

There'are no bushing plates .or special retaining devices. 1 The outstanding advantage from a manufacturing viewpoint is that the arrangement facilitatesassembly and repair." It is evident for example, in originally assembling the clamping rod, the left hand bushing 7 for example is fitted into the complemental bearing opening in the head of the drum and the correspondingreduced or journalend portion of the rod is then slid through the oppositeopening; The last-named'opening of course is minus thebushing l at this ftime. a a

The rod is slid through the opening with the reduced-end passed through and beyond the bushing, allowingit to protrude. The shoulder at the end portion of the knurled central part constitutes a stop. Next, the complemental'bushing 7 at the right hand end is slipped over the reduced end portion 10 of the rod and pressed intoits opening. Then the knurled sleeves are placed'on the protruding end portions and pinned or otherwise secured in place. 'The time saved and 'the reduction in cost, makes this'arrange Inent particularly desirable in a structure of this class. r

' Having thus described my I claimas new is:--

1. Ina structure of the class described, a drum comprising a cylindrical shell provided with a longitudinal abrasive element sl'ot ex tending through the opposite ends of said shell, end-heads carried by the shell andspaced inwardly from the ends of the shell invention, what I and formed with radialslots communicating withthe end portions of said longitudinal slot, a pairof bushing holes in each head on opposite sides of the complemental radial 5 slot,bushings removably fitted in said holes,

and abrasive element clamping means comprising a pair of spaced parallel abrasive clamping rods arranged within the shell and sleeves fastened to the projecting ends and cooperating with each other to grip the edge 'portions'of said abrasive element.

. 2. As a new product'of manufacture, a clampingrod for use in association with an abrasive clamping assembly of the class de scribed, comprising a rod having a central substantially, cylindrical portion provided witha flattened portion .and a knurled antislipping abrasive gripping portion, the ends. of said rod being cylindrical in cross sectionand reduced in diameter 'to simultaneously define shoulders and journals, said journals being smoothsurifaced, a pair of bushings through which said. journals extend, said bushings'abutting said shoulders and being of a diameter substantially equal to the diameter of the central'portion of the rod, and a pair of duplicate externally knurled abrasive element engagingsleeves fastened rigidly on the extending terminalends of said -journals, the intermediate portion of the rod being adapted to engage the corresponding portion of the abrasive element, and said tions of said'abrasive element.

In testimony whereofI afiix my signature.

1 HARRYLL. MYERS.

sleeves being adapted to engage the edge por 

